Synthesis of elymoclavine

ABSTRACT

Elymoclavine is prepared by oxidation of D-6-methyl-8hydroxymethyl-10 Alpha -methoxy-8-ergolene to the corresponding D-8-aldehyde followed by reduction with an active metal in acid medium.

United States Patent 1 1 l 111 3,923,812

Bach ct al. 1 1 Dec. 2, 1975 1 SYNTHESIS OF ELYMOCLAVINE [75] Inventors: Nicholas J. Bach; Edmund C. Primary E'famirller Donald Daus Kornfeld, both of Indianapolis, Ind. b'mmmer Mary Vaughn Attorney, Agent, or Ftrmlames L. Rowe: Everet F. [73] Assignee: Eli Lilly and Company, Indianapolis, S i h Ind,

[22] Filed: Aug. 2, 1974 1 pp 494,149 57 ABSTRACT [52] US, Cl 260/2855; 260/263 PE; 424/261; Elymoclavine is prepared by oxidation of D-fi-mcthyl- 424/250 8-hydroxymethyl-IOa-methoxy-S-ergolenc to the cor- [51] Int. Cl. C07D 457/02 responding D-8-aldehyde followed by reduction with [58] Field of Search 260/2855 n a i metal in acid medium.

[56] References Cited 4 Claims, No Drawings UNITED STATES PATENTS 3,814,765 6/1974 Bernurdi et al. 260/2855 A number of the non-peptide indole alkaloids have SYNTHESIS OF ELYMOCLAVINE been found in fungus cultures grown on Elymns nolh's and other related grasses. These non-peptide alkaloids BACKGROUND OF THE INVENTION include chanoclavine, agroclavine, elymoclavine, and

Compounds based on h li i System I) 5 penniclavine. Of particular interest are agroclavine. an

8-methyl-8-ergolene; elymoclavine, an 8-hydroxymethyl-8-ergolene; and penniclavine, a 8-hydroxymethyl-8- a hydroxy-9-ergolene. These non-peptide alkaloids have been shown to have potent rat prolactin inhibiting aclO tivity comparable to that found with the peptide alkaloid, ergocornine. The synthesis of penniclavine from D-o-methyl-8-hydroxymethyl-IOa-methoxyergolene has been disclosed by Bernardi and Temperilli at the 9th Symposium on the Chemistry of Natural Products,

international Union of Pure and Applied Chemistry held at Ottawa, Province of Ontario, Canada, June 2428, 1974. t

It is an object of this invention to provide a synthesis have a Surprising Variety of Pharmaceutical activities of elymoclavine from optically active starting materi- For cxamplfi lysergic and isolysergic acid are D-srcilrals. Other objects of this invention will become apparboxy-o-methyl-A -ergolines (9,lO-didehydroergolines m f th ifi ti hi h f ll or 9-crgolenes.) The amides of lysergic acid have valuable and unique pharmacologic properties, and include SUMMARY OF THE INVENTION the naturfllly'occurring P p alkaloids; firgocomim, This invention provides a process for the synthesis of rg kryp rg n g in ergosine, g 25 elymoclavine which comprises the oxidation of a D6- amine, etc., synthetic oxytocic alkaloids such as methmethyl 8-hydr0xymethyll()aall 0xy ergolene to yield ergine, and the synthetic hallucinogenlysergic acid dia D 6. h 1-8-f 1 1() ]k orgolene repre cthylamide or LSD. Ergotamine, a 9erg0lcnc, with 21 sented by Structure 11 below. Reduction of this 8-forp ptid s n, has been d in t treatment of myl derivative under conditions which eliminate the migraine and yi both ergocomlne and 3() alkoxy group gives elyrnoclavine (Structure lII below) a'9rgokryptlne have been Show" to be inhibitm's of in excellent yield. The above synthetic procedure is ilprolactin and of dimethylbenzanthracene (DMBA)- l o-m d b h following Reaction Scheme 1.

CH OH CHO CH OH 2 2 i a H HN I ilk- II lll\l i III induced tumors in rats, according to Nagasawa and in which all: is (C -C3) alkyl, as for example, methyl, Meites, Prue. Soc. Exptl. Bio. Med, I35, 469 (1970) ethyl, isopropyl or n-propyl.

and to Heuson et al., Europ. J. Cancer, 353 (1970). In Reaction Scheme 1, above,the procedure of going (See also US. Pat. Nos. 3,752,888 and 3,752,814). from the primary alcohol (I) to the corresponding alde- Non-peptide ergot derivatives, both naturally occurhyde (ll) can be carried out with a variety of oxidative ring and totally or partially synthetic, share these multiprocedures. For example, sodium dichromate in a mixple pharmacological properties with the peptide de rivature of pyridine hydrochloride and pyridine, chromic tives. For example, D--methyl-S-cyanomethylcrgooxide-pyridine complex in methylene dichloride, potasline, was prepared by Semonsky and co-workers, C011, sium dichromate in aqueous sulfuric acid, t-butyl chro- Czec'h. Chem. Commum, 33, 577 (I968), and was mate in benzene, nickel peroxide in benzene, silver carfound to be useful in preventing pregnancy in rats bonate in benzene or silver oxide in phosphoric and Nature, 221, 666 (1969), (See also US. Pat. No. acetic acids,manganese dioxide inavariety of solvents,

3,732,231 by interfering with the secretion of hypolead tetra-acetate in pyridine, sulfur trioxide-pyridine physial leuteotropic hormone and the hypophysial goncomplex in a mixture of dimethyl sulfoxide and triethyladotropins or by inhibiting the secretion of prolactin. amine, tetrachloro-l,Z-benzoquinone (TCBQ) and the [See Seda et al., Reprou'. Fem, 24, 263 (1971) and like can all be employed [see Compendium of Organic Mantle and Finn, id. 441 )l. Semonsky and co-workers, Synthetic Methods, Harrison and Harrison, (John Wiley Coll, Czech. Chem. CUHZHL, 36, 220 (l971), have also and Sons. lnc., New York, 1971) Section 48 at page prepared D-6-methyl-8-ergolinyl-acetamide, a com- 137-143.} We prefer to employ manganese dioxide in pound which is stated to have anti-fertility and anti-lacchloroform or other suitable inert solvent as the oxidiztating effects in rats. The 2-halo derivatives of D-6- ing agent to prepare the aldehyde (ll) from the primary mcthyl-8-cyanomethylergoline and of D-6-methyl-8- alcohol (I). An alternate oxidizing procedure which ergolinylacetamide have been prepared and tested for gives similarly excellent yields consists of using dicyclotheir prolactin inhibiting activity ney, 1- A. hexylcarbodiimide in a solvent consisting of a mixture Celmens, E. C. E. 0 11nd G A- POOTB. 64 th Annual of dimethylsulfoxide, pyridine and trifluoroacetic acid. Meeting Amer. Assoc. Cancer Research, April. 1973). The second step of the above synthetic procedure. the

reduction of the 8-formyl-l()a-alkoxy-8-ergolene with the concommitant elimination of the lOa-alkoxy group can also be accomplished by a variety of reagents. We prefer to employ an active metal in an acidic medium as for example. zinc in acetic acid. Iron in dilute hydrochloric acid can also be employed as can the metal hydride reducing agents as exemplified by lithium aluminum hydride and lithium aluminum (tri-t-butyloxy) hydride. This specification is further illustrated by the following specific example.

EXAMPLE SYNTHESIS OF ELYMOCLAVINE A solution containing 515 mg. of D-6-methyl-8- hydroxymethyl-loz-methoxy-8-ergolene in 150 ml. of chloroform was prepared. Four g. of manganese dioxide were added and the reaction mixture stoppered and stirred at room temperature for one-half hour. The reaction mixture was filtered. and the filter cake washed with chloroform. Evaporation of the filtrate to dryness yielded a residue of D-6-methyl-8-formyl-l00zmethoxy-8-ergolene formed in the above reaction. The residue was chromatographed over a 30 g. of florisil using chloroform containing l to 2 percent methanol as the eluant. Fractions shown to contain the 8-formyl compound by thin layer chromatography were combined and the solvent evaporated therefrom. Recrystallization of the resulting residue yielded purified D-6- methyl-8-formyl-l0a-methoxy-8-ergolene melting at l96-7C. with decomposition.

Analysis Calc.:C, 72.32; H, 6.43; N, 9.92; Found: C, 72.07; H, 6.20; N, 9.65.

A solution was prepared containing 300 mg. of D6- methyl-S-formyl-10a-methoxy8-ergolene in ml. of

acetic acid. 2 g. of zinc dust were added and the reaction mixture stirred at room temperature for 45 minutes. The reaction mixture was filtered and the filtrate poured over ice. The aqueous layer was made strongly basic with 10 percent aqueous ammonium hydroxide, and the alkali-insoluble organic material extracted with chloroform. The chloroform extractions were continued until a chloroform extract showed a negative Van Urk test. The chloroform extracts were combined and washed with saturated aqueous sodium chloride. Evaporation of the organic solvent yielded elymoclavine.

D-6-methyl-8-formyll 0 a-methoxy-8-ergolene can also be prepared by contacting D-6-methyl-8-hydroxymethyll 0a-methoxy-8-ergolene in dimethylsulfoxide solution with a mixture of pyridine and trifluoroacetic acid. Dicyclohexylcarbodiimide is then added and the primary alcohol group oxidized to an aldehyde according to the procedure of Mofjatl J. Am. Chem. 800., 89, 2697 1967 D-6-methyl-8-formyll Oa-methoxy-8- ergolene prepared by this procedure was purified by chromatography and crystallized as in the above example.

A l0oz-ethoxy or lOa-propoxy derivative can be employed in place of D-6-methyl-8-hydroxymethyl-10amethoxy-S-ergolene of the above example. These D-6- methyl-S-hydroxymethyll Oa-alkoxy-8-ergolenes are prepared by the reduction of a D-6-methyl-8-carbomethoxy-l0a-alkoxy-8-ergolene as furnished by the procedure of US. Pat. No. 3,814,765. According to this procedure. methyl lysergate is reacted with a mercuric salt. such as mercuric acetate in a lower aliphatic alcohol for a period from 224 hours at a temperature from 0 to 50C. After the reaction had been completed the 4 excess salt is decomposed by the addition of sodium borohy dride. The IOa-alkoxy group will be derived from the particular lower alkanol employed in the mercuric salt reaction. The 8-carbomethoxy group is then converted to the corresponding primary alcohol by reduction with a metal hydride reducing agent preferably sodium bis (2-methoxyethoxy) aluminum hydride. This latter reaction is set forth in greater detail in the copending application of Kornfeld and Bach, Ser. No. 494,147 filed Aug. 2, l974.

Elymoclavine, the product of the above synthetic procedure is a prolactin inhibitor and gives a 71 percent inhibition of prolactin at a 10 mcg. level in the following test: Adult male rats of the Spraque-Dawley strain weighing about 200 g. were used. All rats were housed in an air-conditioned room with controlled lighting (lights on 6 am. 8 pm.) and fed lab chow and water ad libizum. In each experiment the rats were killed by decapitation, and pl aliquots of serum were assayed for prolactin. Each male rat received an intraperitoneal injection of 2.0 mg of reserpine in aqueous suspension 18 hours before administration of elymoclavine. The purpose of the reserpine was to keep prolactin levels uniformly elevated. The elymoclavine was dissolved in 10% ethanol at a concentration of l0 meg/ml, and were injected intraperitoneally at a standard dose of 50 meg/kg. Each compound was administered to a group of 10 rats, and a control group of 10 intact males received an equivalent amount of 10 percent ethanol. One hour after treatment, all rats were killed by decapitation, and the serum was collected and assayed for prolactin as previously described. The results were evaluated statistically using Students t test to calculate the level of significance, p. The difference between the prolactin level of the treated rats and prolactin level of the control rats, divided by the prolactin level of the control rats gave the percent inhibition of prolactin secretion attributable to elymoclavine.

As a prolactin inhibitor, elymoclavine is potentially useful in the treatment of inappropriate lactation such as postpartum lactation and galactorrhea. in addition, it can be used to treat prolactin-dependent adenocarcinomas and prolactin-secreting pituitary tumors as well as the following disorders: Forbes Albright syndrome, Chiari-Frommel syndrome, gynecomastia itself and gynecomastia occurring as a result of estrogenic steroid administration for prostatic hypertrophy, fibrocystic disease of the breast (benign nodules), prophylactic treatment of breast cancer, and breast development resulting from the administration of psychotropic drugs, for example, thorazine, or for prostatic hypertrophy itself.

In employing elymoclavine to inhibit prolactin secretion, the compound or a salt thereof with a pharmaceutically-acceptable acid is suspended in corn oil and the suspension injected parenterally or fed to a female mammal in amounts varying from 0.01 to 10 mg/kg/day of mammalian weight. Oral administration is preferred. lf parenteral administration is used. the injection is preferably by the subcutaneous route using an appropriate pharmaceutical formulation although other modes of parenteral administration such as intraperitoneal, intramuscular, or intravenous administration are equally effective. In particular, with intravenous or intramuscular administration, a soluble pharmaceutically-acceptable salt of elymoclavine preferably the methanesulfonate or maleate salt, is customarily employed. For oral administration, the compound either as the free base or in the form of a salt thereof can also be mixed with standard pharmaceutical excipients and loaded into empty telescoping gelatin capsules or pressed into tablets.

We claim:

1. A two-step process for producing elymoclavine which comprises the steps of( l oxidizing a D-6-methyl-8-hydr0xymethyl-l0a-alkoxy-8-ergolene of the formula CH OH 2 wherein alk is (C1-C3) alkyl to yield a D-6-methyl-8- formyl-l0a-alkoxy-8-ergolene of the formula UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 5,925,812

Q DATED December 2, 1975 INVENTOR(S) Nicholas J. Bach, et 8.1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Column 1, line 69, "E. c. E. 0." should be -E. c.

Kornfeld-.

Signed and Scaled this [SEAL] D 0f June 1976 Attest:

RUTHCM Mmmg 5 c. MARSHALL mun Commissioner uj'Patenls and Trademarks 

1. A TWO-STEP PROCESS FOR PRODUCING ELYMOCLAVINE WHICH COMPRISES THE STEPS OF (1) OXIDIZING A D-6-METHYL-8-HYDROXYMETHYL-10A-ALKOXY-8-ERGOLENE OF THE FORMULA
 2. A process according to claim 1 in which the oxidizing agent employed in step 1 is manganese dioxide.
 3. A process according to claim 1 in which the oxidizing agent employed in step 1 is dicyclohexylcarbodiimide in a dimethylsulfoxide-trifluoroacetic acid solvent.
 4. A process according to claim 1 in which the reducing agent in step 2 is zinc in acetic acid. 